Nav: Home

Rising temperatures threaten stability of Tibetan alpine grasslands

May 10, 2017

A warming climate could affect the stability of alpine grasslands in Asia's Tibetan Plateau, threatening the ability of farmers and herders to maintain the animals that are key to their existence, and potentially upsetting the ecology of an area in which important regional river systems originate, says a new study by researchers in China and the United States.

Though temperature changes could destabilize the fragile ecosystem of the area, variations in rainfall appear to have no similar effect. The study involved varying two factors likely to change with a warming climate - temperature and rainfall - in test plots over a five-year period. The project is believed to be the first to simultaneously examine the effects of temperature and rainfall changes on ecosystem stability.

"We were concerned about the variability of the total community plant cover over time," said Lin Jiang, a professor in the Georgia Tech School of Biological Sciences. "Significant warming could reduce the stability of the grasslands, which would increase the variability of plant biomass production that could be a significant issue for people living in the region. We believe the effects of climate change could be particularly dramatic in this area."

The research, conducted by scientists from Peking University, the Chinese Academy of Sciences and the Georgia Institute of Technology, was scheduled to be published May 10 in the journal Nature Communications. The research was supported by the National Basic Research Program of China, the National Nature Science Foundation of China and the U.S. National Science Foundation.

The Tibetan Plateau is an area of about 2.5 million square kilometers in which summertime high temperatures seldom rise above 25 degrees Celsius and nighttime temperatures could drop below freezing even in the summer. Because of the altitude, temperature extremes and high winds, more than two-thirds of the Plateau is grassland used for grazing yak, sheep and other animals. About 9.8 million people live in the area, which is also the source for several of Asia's major river systems.

"Our results suggest that under a warmer climate, the ecosystem would provide less forage production in drought years, and more biomass production in wet years - which is undesirable," said Jin-Sheng He, a professor in the Department of Ecology, College of Urban and Environmental Sciences at Peking University. "Reduced plant production temporal stability could mean that this alpine ecosystem may not be able to provide stable forage for the livestock that local people rely on. Reduced stability may also have consequences for other ecosystem services, such as climate regulation and water conservation."

The researchers found that the stability of the grasslands was affected not by the richness of plant species, but by the effects on dominant species and the asynchrony of the species.

"We found that climate warming lowers stability through increasing species synchrony in which the biomass of a few dominant species increased while that of most rare species declined," said He. "That indicates the alpine grasslands that have well adapted to cold environments owing to their long-term evolutionary history may be jeopardized in the future."

Experimentally, the researchers created test plots in which some were heated to two degrees Celsius above the surrounding grasslands. At the same time, the researchers varied the amount of rainfall onto the plots, with some sections receiving 50 percent more water, and others receiving 50 percent less. There were also control sections in which temperature and rainfall were not adjusted. Each of the six conditions were replicated six times, for a total of 36 test plots.

Over a period of five years, the researchers studied the growth of different grass species by weighing the biomass production from the different test plots. The research was done at the Haibei Alpine Grassland Ecosystem Research Station of the Chinese Academy of Sciences.

Jiang was surprised that the dramatic variations in rainfall didn't affect the grass species, and hadn't expected much impact from the temperature change, which translates to about 3.6 degree Fahrenheit. "The plants appear to be able to tolerate significant variations in the amount of water available," he said.

While the Tibetan Plateau is unique for its size and high average altitude, there are other areas of the world with similar conditions. "If these findings can be generalized to other alpine ecosystems, we may need to be concerned about large variations in biomass production in these other areas, as well," Jiang added.

The study adds to knowledge about the Tibetan plateau, which has not been well studied because of its geographical isolation and harsh climate.

"The Tibetan plateau is sometimes called the third pole because there are so many high mountains and so much of the area is covered with snow and ice," said Jiang. "Ecologically, it is a very important region, but relatively few ecological studies have ever been done there."
This study was supported by the National Basic Research Program of China (2014CB954004 and 2014CB954003), the National Nature Science Foundation of China (31630009 and 31361123001), the U.S. National Science Foundation (DEB-1257858 and DEB-1342754), and the 111 Project (Grant No. B14001) of China. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the sponsoring agencies.

CITATION: Zhiyuan Ma, Huiying Liu, Zhaorong Mi, Zhenhua Zhang, Yongui Wang, Wei Xu, Lin Jiang and Jin-Sheng He, "Climate warming reduces the temporal stability of community biomass production," (Nature Communications, 2017).

Georgia Institute of Technology

Related Climate Change Articles:

The black forest and climate change
Silver and Douglas firs could replace Norway spruce in the long run due to their greater resistance to droughts.
For some US counties, climate change will be particularly costly
A highly granular assessment of the impacts of climate change on the US economy suggests that each 1°Celsius increase in temperature will cost 1.2 percent of the country's gross domestic product, on average.
Climate change label leads to climate science acceptance
A new Cornell University study finds that labels matter when it comes to acceptance of climate science.
Was that climate change?
A new four-step 'framework' aims to test the contribution of climate change to record-setting extreme weather events.
It's more than just climate change
Accurately modeling climate change and interactive human factors -- including inequality, consumption, and population -- is essential for the effective science-based policies and measures needed to benefit and sustain current and future generations.
Climate change scientists should think more about sex
Climate change can have a different impact on male and female fish, shellfish and other marine animals, with widespread implications for the future of marine life and the production of seafood.
Climate change prompts Alaska fish to change breeding behavior
A new University of Washington study finds that one of Alaska's most abundant freshwater fish species is altering its breeding patterns in response to climate change, which could impact the ecology of northern lakes that already acutely feel the effects of a changing climate.
Uncertainties related to climate engineering limit its use in curbing climate change
Climate engineering refers to the systematic, large-scale modification of the environment using various climate intervention techniques.
Public holds polarized views about climate change and trust in climate scientists
There are gaping divisions in Americans' views across every dimension of the climate debate, including causes and cures for climate change and trust in climate scientists and their research, according to a new Pew Research Center survey.
The psychology behind climate change denial
In a new thesis in psychology, Kirsti Jylhä at Uppsala University has studied the psychology behind climate change denial.

Related Climate Change Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#529 Do You Really Want to Find Out Who's Your Daddy?
At least some of you by now have probably spit into a tube and mailed it off to find out who your closest relatives are, where you might be from, and what terrible diseases might await you. But what exactly did you find out? And what did you give away? In this live panel at Awesome Con we bring in science writer Tina Saey to talk about all her DNA testing, and bioethicist Debra Mathews, to determine whether Tina should have done it at all. Related links: What FamilyTreeDNA sharing genetic data with police means for you Crime solvers embraced...